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Exploding Peerless Pinnacle Boiler

SUPER DAN P&H Member Posts: 48
I serviced a Peerless Pinnacle boiler which was filthy. I cleaned the heat exchanger, corrected the exhaust distance, piped it primary/ secondary, cleaned the igniter/ flame sensor, checked the combustion levels for proper operation.

A week later the customer had a f 9 error code. When I went to reset the controller on start up I heard a little explosion in the heat exchanger. Yet it ran normally after that. Does anyone know why that happened.


  • Tim McElwain
    Tim McElwain Member Posts: 4,593
    Did you replace

    the fiber backing in the heat exchanger? Perhaps left somethings a little wet inside the chamber. Did you flush the condensate line and check the flue passages? All gaskets in place or replaced and tightened correctly.

    How long had it gone without cleaning?
  • Slimpickins
    Slimpickins Member Posts: 333
    Check burner

    If you have the Pl - T50 or Pl-T80 you may want to check the burner. It should be tight with no movement. If not, remove it and clean the screws incl. below the screw head where it mates up with the burner. Also rinse out the burner under a faucet and clean the flange where the screws fasten. It rectifies the flame sense through the burner so it's important to make sure the screws holding the burner are clean and tight. Also you will need to replace the burner gasket during all this. Not sure if this could have caused the explosion. I would check your combustion set up again.
    SUPER DAN P&H Member Posts: 48
    Peerless Pinnacle Boiler

    Thanks guys. Its a P-199 nat gas boiler. Peerless tech support told me it could be wet insulation. Just wanted to double check this. This boiler is 5 yrs old and never cleaned. They spent $3500 on repairs w/ another company  w/o every correcting the problems. I was hoping to save this boiler for these nice people. Should I be concerned about this problem. Will it dry out by itself?  Is there anything else I can do to prevent these f 9 error codes? Thanks,Dan.
  • Slimpickins
    Slimpickins Member Posts: 333
    replace target wall!

    Yes, replace the target wall. That is the dirtiest Gionnoni I've ever seen and you would need to remove the target wall to give that heat exchanger the cleaning it needs, How did you clean it? I use Rydelyme when they're that bad or you can use CLR, just let it soak a while. You should have vacuumed as much crud as possible before flushing heat exchanger. The screw and washer holding the target wall can be tricky to remove. Just make sure you don't breathe the fibers from the target wall, wet it down before removing. To install a replacement target wall, I use my shop vac and suck up the target wall against the end of the hose and guide it into the heat exchanger and cut the power once in place. When flushing, make sure you're getting good flow thru the condensate line, you may need to squeeze the rubber Ptrap to loosen debris. Also, I've used the shop vac to blow air backwards thru the P trap to break loose. if you can't find a Peerless target wall you can use a Munchkin, Lochinvar Knight, NYT target wall, they're all the same size. Good luck! 
    SUPER DAN P&H Member Posts: 48

    Is it true this buildup is caused when the air intake and exhaust are too close? I shop vac'd as much as possible. Then removed the target wall. Then CLR'd the heat exchanger. After 10 min of breaktime I ran a 1/2" fitting brush round and round till I got to the SS exchanger. Then flushed lots of water thru it till it started draining well. Polished my igniters w/ soft grit cloth. Reinstalled my target wall and repiped boiler. On start up it ran smooth. A week later get a f 9 error code. Reset boiler and heard a little explosion in there. I watched it run and condensate was flowing. After that it ran normal for 24 hrs and another f 9 code popped up again. And here we are...
  • meplumber
    meplumber Member Posts: 678
    Don't use a metal bristle brush on these heat exchangers.

    You should always use a stiff plastic or nylon bristle brush to clean these.  Never use a steel bristle.  Let the CLR, Simple Green or Rydelyme do the work, then break it up with the nylon brush.  I use a round toilet brush.
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,840
    Nylox Brushes...


    I've run this method by two Chief Engineers who utilize Gianonni HXers in the construction of their boilers, and they both agreed that this is a great application. Nylon with impregnated abrasives.

    On some deeper combustion chambers, you will need a good stiff extension to get the the back of the box. That or a straight shaft drive high speed grinder (rare and expensive).

    How many years did this fire box go without cleaning? Is it anywhere near a salt water source?

    Ugly for sure.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • Jr_12
    Jr_12 Member Posts: 38
    Most likely burner gasket

    Typically on "exploding" units I find the cause to be

    1.Burner gasket missing or damage to burner flange

    2.Igniter arcing from either a wet refractory or damage

    3.Swirl plate being damaged(you may or may not have one on this unit

    That picture almost makes me think you might have a leak in the coil though. Normally the crud inside looks like coffee grounds, not calcium/scale. I could very well be wrong though.

  • Jr_12
    Jr_12 Member Posts: 38
    that target wall looks fine

    I wouldnt replace the target wall unless it's cracked or missing pieces. I would like to see a picture of the burner/faceplate assembly
  • rlaggren
    rlaggren Member Posts: 160
    cleaning tools

    >>  On some deeper combustion chambers, you will need a good stiff extension

    to get the the back of the box. That or a straight shaft drive high

    speed grinder (rare and expensive).
    disclaimer - I'm a plumber, not a heating pro.
    SUPER DAN P&H Member Posts: 48

    This boiler is in Ridgewood, NJ. Far from any salt or fresh waterways. Its never been cleaned before I took on this project.I will be servicing it on an annual basis from now on though.
This discussion has been closed.